When electron beams (cathode rays) emitted for sterilizing cellular microorganisms (hereinafter referred to as a contaminant) collide with metallic shields (containing lead) disposed as shields, the electron beams are attenuated and then are reflected and diffracted as X-rays in a widely diffused state. For example, if electron beams collide with the shield three or four times, although depending on the intensity thereof, X-rays can be attenuated to a degree of intensity that does not affect a human body.
The intensity of electron beams passing through a plastic container may be increased to simultaneously sterilize the inner surface and the outer surface of the container. As the intensity of electron beams increases, the material may be changed in quality, colored, deformed, or caused to give off an odor. Thus, the use of an electron-beam deflector has been proposed such that the deflected electron beams are introduced to the inner surface of a container through the inlet to simultaneously sterilize the inner and outer surfaces of the container. However, the introduction of sufficient electron beams to the inner surface of the container cannot be expected.
In recent years, for example, patent literature 1 is proposed as a technique of sterilizing the inner surface of a container with an electron beam irradiation nozzle inserted into the inlet of the container. Patent literature 2 proposes the layout of an electron beam irradiation nozzle for sterilizing an inner surface and an electron beam irradiator for sterilizing an outer surface.